SEOUL, July 25 (Reuters) - South Korea's economy swung back to growth in the second quarter, dodging a technical recession, although the expansion was mostly driven by government spending, suggesting the central bank may need to cut rates again to stoke demand.

Gross domestic product grew by a seasonally adjusted 1.1% in the April-June period from the first quarter, central bank estimates showed, just beating the median forecast of 1.0% growth tipped in a Reuters survey of 12 economists.

However, the Bank of Korea estimates showed the economy would have contracted without increased government spending, following previous quarter's surprise contraction.

"Details of the GDP data confirmed the economy has been dependant on government spending and support my expectation of another interest rate cut in the fourth quarter," said Park Sang-hyun, economist at HI Investment & Securities.

Heavily reliant on exports of chips, smartphones, autos and ships, South Korea's economy has been hit especially hard by the year-long China-U.S. trade dispute, which has hurt supply chains and global growth.

BOK estimates showed government spending contributed 1.3 percentage points to second-quarter GDP while private-sector activity presented a 0.2 percentage point drag as companies slashed investment due to the uncertain outlook.

Last week, the BOK cut interest rates for the first time in three years, earlier than market expectations for a cut in August, and trimmed its 2019 economic growth forecast to a decade low of 2.2% from the previous 2.5%.

South Korea's economy shrank 0.4% in the first quarter due to delays in government spending as private investment also slowed.

On a year-on-year basis, Asia's fourth-largest economy expanded 2.1% in the second quarter, compared with 2.0% growth forecast in the poll and 1.7% growth in the first quarter, the central bank estimated.

Merchandise exports returned to growth of 2.3% in the April-June period after a 3.2% contraction in the first, which was the worst reading since the final quarter of 2017.

But export prospects remain uncertain as Japan has curbed chip and display production materials shipments to South Korea, which Seoul says is related to a diplomatic row over compensation of forced labour during World War Two.

The BOK said in a report to parliament on Tuesday that Japan's export curbs were one of the top three risks to the domestic economy. Governor Lee Ju-yeol added that this year's growth could dip further due to the curbs.

Analysts have downgraded their forecasts for 2019 growth, with some seeing growth falling short of 2%. (Editing by Jacqueling Wong, Sam Holmes)